Passenger seats for use on aircraft, sea-going passenger ferries and luxury coaches comprise a seat pan and a reclinable back-rest. Generally, the seat pan is fixedly secured to a support frame that is anchored to a floor of the vehicle. A disadvantage of this arrangement is that as the back-rest is reclined, it impinges on the space of a passenger using a seat positioned behind the one being reclined. Some passenger seats, particularly those which are used in the business-class and first class sections of passenger aircraft, additionally include a leg-rest that can be moved between a raised position and a lowered position. Often, the back-rest reclining and leg-rest moving mechanisms are linked, so that as the back-rest is reclined from an upright position to a reclined position, the leg-rest is moved towards the raised position. Whilst the additional comfort provided by the leg-rest is recognised, a disadvantage with this arrangement is that when the leg-rest is raised, the space (or "foot well") adjacent the floor under the back-rest and seat pan of a seat in front of the one being reclined cannot be properly utilised.
At the time of writing, there is a trend towards providing passenger seats in which the back-rest and leg-rest can be manoeuvred to form a substantially flat surface with the seat pan on which a passenger can lie down for sleeping. In some cases, where the seat pan is fixedly secured to a support frame as previously mentioned, this is simply achieved by allowing the back-rest and leg-rest to be respectively reclined and raised further than was the case previously, so as to be substantially coplanar with the seat pan. Of course, this exacerbates the problems discussed above associated with the use of reclining seat-backs and lifting leg-rests, and requires the pitch between adjacent rows of seats to be substantially increased.
WO-A-96/18537 of British Airways Plc discloses a passenger seat for an aircraft that comprises a housing that can be fixedly secured to a cabin floor of the aircraft, and a movable portion comprising a back-rest, a seat pan and a leg-rest. The seat pan is hinged to the back-rest and is supported at a point remote from the hinge by a trolley, which trolley is adapted for translational movement on the cabin floor between a retracted position and an extended position relative to the housing. A motorised screw-drive is fitted between the trolley and the housing for driving the trolley between these two positions. Two spaced arms that are attached to opposing sides of the seat pan each comprise a guide member that is accommodated within a track formed in a respective side wall of the housing. The track is shaped, so that as the trolley is moved between the retracted and extended positions, the part of the seat pan adjacent the hinge to the back-rest is raised or lowered, so that the seat pan is pivoted about its mounting on the trolley through pre-selected orientations. Each side wall of the housing further comprises an additional track that accommodates a second guide member, which guide member is fixedly secured to a respective side of the back-rest. The additional tracks are configured so that as the trolley is moved between the retracted and extended positions, and the seat pan is rocked about its mounting on the trolley, the back-rest is progressively reclined between an upright position and a fully reclined position, with the recline angle of the back-rest portion at any given position of the trolley being defined by the position of the hinge between the seat pan and back-rest and the position of the second guide members in their respective additional tracks.
The passenger seat of WO-A-96/18537 is arranged so that as the back-rest is reclined the back-rest remains within the housing, so that it does not interfere with the space of a passenger using a seat behind the one being reclined. In the fully reclined position, the seat pan and back-rest are oriented such that they are substantially coplanar with one another to form a flat surface for a passenger to sleep on. The passenger seat of WO-A-96/18537 further comprises a leg-rest that is mounted pivotably on the trolley adjacent the seat pan mounting. A second motorised screw-drive is provided for moving the leg-rest between a lowered position and a raised position in which the leg-rest is substantially coplanar with the seat pan and back-rest to extend the sleeping surface.
The passenger seat of WO-A-96/18537, whilst it solves the problem of the back-rest being reclined into a space of another passenger, has a number of serious disadvantages. First of all, the trolley used for supporting the seat pan, and for driving the movable part of the seat between the retracted and extracted positions is a complex, and thus expensive component to manufacture and adds substantially to the weight of the seat. Secondly, as the seat pan is supported on the trolley remote from the hinge to the back-rest, the height of the seat pan where it is mounted on the trolley above the cabin floor is fixed. Thus, a foot well provided in the rear of a seat in front of the one being reclined cannot be utilised fully when the seat is in the fully reclined position, with the leg-rest raised.
A further disadvantage of the seat of WO-A-96/18537 is that the screw-drive mechanism used for driving the trolley into and out of the housing is located within the housing, beneath the seat pan and back-rest, in juxtaposition with the cabin floor. The screw-drive mechanism thus impinges on the space towards the bottom of the housing which is available for use as a foot well, and moreover is positioned where it is likely to collect dust, dirt and other detritus which may, in time, be injurious to proper operation of the screw-drive mechanism.